The present invention relates to an integrally molded cross-flow fan having a number of equally angularly spaced, radial thin vanes, for use in an air-conditioning unit, an air blower, or the like, and a method of integrally molding such a cross-flow fan.
One conventional elongate cross-flow fan molded of plastics comprises a plurality of annular ribs spaced at regular intervals and a plurality of equally angularly spaced, radial thin vanes extending axially between each pair of the annular ribs.
Heretofore, the conventional cross-flow fan is molded of plastics as follows: A cross-flow fan segment comprising an annular rib and a plurality of equally angularly spaced, radial thin vanes is integrally molded of plastics. After the cross-flow fan segment has been molded, the mold by which the spaced vanes are formed are axially withdrawn from the cross-flow fan segment. In this manner, a plurality of integrally molded cross-flow fan segments are fabricated. Then, the cross-flow fan segments are bonded together at the ribs, thereby making up an elongate cross-flow fan.
The above manufacturing process is however tedious, time-consuming, and does not lend itself to mass-production. Accordingly, the conventional cross-flow fan is expensive to manufacture.
Since the entire cross-flow fan is composed of bonded cross-flow fan segments, it has a low degree of roundness or poor weight balance, and hence may cause vibration or noise during operation. To avoid this problem, an unbalanced cross-flow fan must be balanced by a balancing weight attached thereto. Such a balancing adjustment process adds to the cost of the cross-flow fan.